Electron discharge device having a vacuum sealing member and mechanical support means between the tube main body and the collector



Aug. 15, 1967 s, MERCER ET AL 3,336,491

ELECTRON DISCHARGE DEvIcE HAVING A vAcuuM SEALING MEMBER AND MECHANICAL SUPPORT MEANS BETWEEN THE TUBE MAIN BODY AND THE COLLECTOR Filed May 6, 1964 FIG. l

I Al v ADJUSTABLE SUPPORTING-I6 MEANS I \f\ I T L INVENTORS STANLEY 1.. MERCER ARMAND STAPRANS ATTORNEY 3,336,4M ELECTRON DISCHARGE DEVICE HAVING A VACUUM SEALHN G MEMBER AND MECHAN- ICAL SUPPORT MEANS BETWEEN THE TUBE MAIN BODY AND THE COLLECTOR Stanley L. Mercer, Palo Alto, and Armand Staprans, Los Altos, Calif., assignors to Varian Associates, Palo Alto, Calif, a corporation of California Filed May 6, 1964, Ser. No. 365,473 11 Claims. (Cl. 313-148) ABSTRACT OF THE DISCLOSURE A high frequency electron discharge device is provided with independent vacuum sealing and support structures between the collector and the tube main body portion for devices using metal bodies and metal collectors. Adjustable supporting means between the collector and the tube main body permit operation of the collector with respect to the tube main body in either shorted or non-shorted conditions.

This invention relates in general to the field of high frequency electron discharge devices such as the klystron, traveling wave tube, etc., and more particularly to such devices having improved collector to main body supporting structures.

It is conventional practice at present to provide D.C. isolation between the main body portion and the collector portion of high frequency electron discharge devices. A depressed or D.C. isolated collector is used for a number of reasons such as, for example, to improve overall tube operating efficiency and/ or to provide means for readily measuring collector and body currents in order to determine beam transmission efiiciency. However, in utilizing insulated collectors in higher powered tubes problems of providing both adequate structural strength as well as adequate insulation between the collector portion and main body portions of the tube are encountered. These problems are due to the large weights of the collector portions which may approach 1,000 or more pounds. Such weights impose extremely high stresses on ceramics and other insulating parts or members which are used to support the collector to the tube main body while maintaining vacuum integrity as well as DC. isolation therebetween. Conventional practice would dictate the combination of the support and vacuum sealing functions in a single annular ceramic member which would provide D.C. isolation as well as physical support between the collector and the tube main body. However, the high cost of a ceramic support member which is capable of supporting great weight-s as well as the difficulties involved in fabrication techniques to provide adequate built-in strength in order to maintain vacuum integrity under conditions of operation which produce thermal differential expansion between the collector and the tube main body preclude such a simple design approach. The present invention obviates the aforementioned difficulties through the utilization of independent vacuum sealing and support structures between the collector and the tube main body portion of high frequency electron discharge devices. The present invention furthermore through the utilization of novel adjustable supporting means between the collector portion and the tube main body portion of the high frequency electron discharge device permits operation of the collector with respect to the tube main body in either shorted or non-shorted conditions.

It is therefore the object of the present invention to provide a structurally improved high frequency electron discharge device.

A feature of the present invention is the provision of a United States Patent high frequency electron discharge device having means for supporting the collector portion of said device in an adjustable relationship with respect to the tube main body portion thereof.

Another feature of the present invention is the provision of a high frequency electron discharge device having means for supporting the collector portion of said device with respect to the tube main body portion thereof in an adjustable relationship therewith, said adjustable supporting means being independent of and exterior to the vacuum envelope of said device.

Another feature of the present invention is the provision of a high frequency electron discharge device having independent vacuum sealing and mechanical support means between the collector portion of said device and the tube main body ortion of said device.

These and other features and advantages of the present invention will become more apparent upon a perusal of the following specification taken in connection with the accompanying drawings wherein,

FIG. 1 is an enlongated longitudinal view partially cut away and sectioned depicting a high power klystron tube incorporating the novel features of the present invention.

FIG. 2 is an elevational view partly in section taken along the lines 2-2 of FIG. 1 in the direction of the arrows.

FIG. 3 is a fragmentary sectional view taken along the lines 3-3 of FIG. 2 depicting the details of a portion of the novel support and vacuum sealing techniques of the present invention.

Referring now to FIG. 1, there is depicted therein a high frequency electron discharge device 4 of the klystron type which is capable of operation as an amplifier in the multi-megawatt region. The klystron depicted in FIG. 1 includes a beam forming and projecting means or an electron gun end portion 5 coupled to a main body portion 6 including the interaction region surrounded by the vacuum envelope portion 9 of the klystron which in turn is coupled in a vacuum sealed relation to a beam collector member 7. Reference to any suitable text may be made in order to find descriptions of typical electron guns and klystron interaction portions which are exemplified by sections 5 and 6 in FIG. 1. Input and output waveguides 10 and 11 respectively are utilized to provide coupling means for the RF. energy to be amplified. The collector 7 shown at the downstream end of the device is an extremely large device the details of which do not form part of the present invention. Any conventional preferably fluid cooled collector capable of dissipating high powers will suffice for the purposes of illustration. The large collector 7 is supported in a rigid manner with respect to the tube main body vacuum envelope portion 9 by means of preferably four adjustable supporting means 13, 14, 15, 16 as shown in FIGS. 1, 2 and 3.

The tube depicted in FIG. 1 is preferably magnetically focused by conventional means, such as by a solenoid which is not shown. A conventional pole piece 17 of any suitable material such as soft iron is positioned at the downstream portion of the tube as shown. The adjustable supporting means 1316 are insulatedly and rigidly affixed between the pole piece 17 and the collector 7 as best seen in FIG. 3. The vacuum seal between the collector and the pole piece portion of the tube body includes an annular ceramic ring 19, sandwiched between, supported by and brazed to a pair of flexible annular preferably Kovar washer members 20-21 as shown. Washer members 2021 are in turn preferably welded to annular stepped ring-like members 23-24 which are also preferably of Kovar and which in turn are brazed to the pole piece and collector members respectively.

The pole piece 17 is preferably made in two annular coaxial interfitting sections 17 (a) and 17(b) respectively,

which are preferably fixedly secured together by means of any suitable number of screws such as 26. The pole piece section 17(a) is preferably provided with a copper sheath 27 which forms a cone shaped beam defining aperture between the output cavity 23 surrounded by the vacuum envelope portion 9 of the tube main body to which the pole piece section 17 (a) is vacuum sealed by any suitable known metal joining technique. A collector wall portion 30 is preferably made from stainless steel and is advantageously provided with interior copper lining 31 provided with spaced grooves 32 as shown through which cooling fluid may be circulated in order to dissipate the thermal energy generated by the electron beam impinging on the collector internal surfaces.

A gap g between copper clad pole piece section 17 (a) and the copper clad collector wall portion 30 may be varied from the shorted to the non-shorted condition by means of adjustable mechanical supporting means 13-16 as will be explained in more detail hereinafter. The expansion-support rings 20, 21 are provided with a convolution 33 and a stepped configuration respectively in order to provide suflicient flexibility for the insulated vacuum joint portion to allow for expansion and contraction under various ambient and environmental conditions as well as operating and experimental conditions in the DC. isolated (insulated) and shorted conditions. The expansion-support rings 20, 21 are preferably welded to a pair of stepped Kovar support ring-like members 23, 24 which provide additional flexibility. It is obvious that many variations of the above mentioned expansion-support members are within the scope of one skilled in the art. For example, the members 20, 23 may be made of a single shaped piece as well as the members 21, 24 and obviously many variants in the shapes of the expansionsupport members are possible without departing from the scope of the present invention.

The adjustable support means 13-16 each include an elongated stud member 35 having threaded end portions 36, 37 as shown. The one end of stud 35 is preferably rigidly threaded into a mounting washer 38 which is fixedly secured to the collector end wall 30 by any suitable means such as screws 39. Each stud 35 is rigidly yet adjustably secured to the pole piece 17 in DC. isolated relation thereto by means of a plurality of annular dielectric washers in the following manner. A central insulating washer 40 preferably of alumina or other equivalent types of dielectric insulating material is positioned within a bore 41 extending through the pole piece 17 and the stud 35 is fixedly secured therein. A pair of alumina or the like washers 42, 43 are disposed on opposite sides of the pole piece 17 and a pair of ductile washers 44, 45, such as, for example, copper, are sandwiched between insulating washers 42, 43 and another similar pair of insulating washers 46, 47 which in turn are secured by adjustable locking nuts 48, 49 threaded on stud 35 as shown. A pair of locking washers 56, 57 may be disposed between theheads of the adjustable locking nuts 48, 49 and insulating washers 46, 47 as shown.

Pole piece 17 is preferably made of two interfitting coaxial sections 17 (a), 17 (b) in order to facilitate assembly of the vacuum seal and adjustable mechanical support means, For example, suitable mounting means may be used to secure the collector in fixed relation with respect to the tube main body vacuum envelope portion 9 with pole piece section 17(b) removed in order to permit ready access for welding support rings 21, 24 together. Then pole piece 17 (b) may be fixed in place together with adjustable support means 13-16 and any desired adjustments with regard to gap spacing g can be made with adjustable locking nuts 48, 49. The ductile washers 44, 45 permit differential thermal expansion to occur in each of the adjustable support means 13-16 with minimal danger of cracking of the insulating washers. The ductile washers 44, 45 further permit adjustable locking nuts 48, 49 to be tightened to a degree not otherwise possible without causing breakage of the insulating washers.

The above outlined construction of the adjustable support means 13-16 provides a rigid mechanical support function between the tube main body portion 6 (including in the preferred embodiment depicted in FIG. 1 pole piece 17 and vacuum envelope portion 9) and the collector 7 independent of and exterior to the vacuum envelope and insulating vacuum seal member 19 of the device while permitting both D.C. isolation and shorting of the collector 7 with respect to the tube main body portion 9.

Gap g is varied from a shorted to a non-shorted condition by simple rotation of the locking nuts, relative movement of washers and member 17 (b) on studs 35 and then tightening of the adjustable locking nuts 48, 49 to any desired position on the threaded portion of studs 35. The terminology tube main body includes that portion of the vacuum envelope 9 which is upstream from the pole piece member 17. Pole piece member 17 is illustrative of any mounting flange and member 17 is not to be restricted to a magnetic pole piece nor is it necessary that member 17 form part of the vacuum envelope since quite obviously the adjustable mechanical support techniques of the present invention are applicable to any electron discharge device, wherein two portions thereof are desired to be maintained in DC. isolation and require a vacuum seal therebetween, such as, for example, periodic permanent magnet or electrostatically focused devices. Quite obviously pole piece 17 could be physically attached to the tube main body vacuum envelope 9 on the external surface thereof exteriorly of the evacuated portions.

Since many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A high frequency electron discharge device including a beam forming and projecting means coupled at the upstream end of said device to a tube main body portion and a metal beam collector member means coupled to said tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said tube main body and said metal beam collector member means, said tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support means physically yet insulatedly interconnecting said tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said tube main body, beam-forming and projecting means and metal beam collector means.

2. A high frequency electron discharge device including a beam forming and projecting means coupled at the upstream end of said device to a metal tube main body portion and metal beam collector member means coupled to said metal tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said metal tube main body and said metal beam collector member means, said metal tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support means physically yet insulatedly interconnecting said metal tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said metal tube main body, beam-forming and projecting means and metal beam collector member means.

3. The device defined in claim 2 wherein said mechanical support means is adjustable.

4. The device as defined in claim 2 wherein said annular dielectric insulating member is a ceramic ring vacuum sealed to an annular flexible expansion support ring like member.

5. A high frequency electron discharge device including a beam forming and projecting means coupled at the upstream end of said device to a tube main body portion and a metal beam collector member means coupled to said tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said tube main body and said metal beam collector member means, said tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support means physically yet insulatedly interconnecting said tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said tube main body, beam-forming and projecting means and metal beam collector means, said tube main body having a pole piece rigidly secured thereto at a downstream end portionthereof, said mechanical support means being physically yet insulatedly secured to said pole piece and to said metal collector member means.

6. A high frequency electron discharge device including a beam forming and projecting means coupled at the upstream end of said device to a tube main body portion and a metal beam collector member means coupled to said tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said tube main body and said metal beam collector member means, said tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support means physically yet insulatedly interconnecting said tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said tube main body, beam-forming and projecting means and metal beam collector means, said mechanical support means being adjustable and including at least one stud member fixedly secured to said collector member means at the one end thereof and adjustably secured to said tube main body at the other end thereof.

7. A high frequency electron discharge device includ ing a beam forming and projecting means coupled at the upstream end of said device to a tube main body portion and a metal beam collector member means coupled to said tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said tube main body and said metal beam collector member means, said tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support physically yet insulatedly interconnecting said tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said tube main body, beamforming and projecting means and metal beam collector means, said tube main body having a pole piece rigidly secured thereto at a downstream end portion thereof and at least one stud member physically yet insulatedly interconnecting said pole piece and said metal collector member means.

8. The device as defined in claim 7 wherein said stud member is fixedly secured to said collector means at the one end thereof and fixedly yet adjustably secured to said pole piece at the other end thereof, said stud member having threaded end portions, said stud member being positioned within and extending through an insulating member disposed within a bore within said pole piece member, and a pair of adjustable locking nuts threaded on said threaded end portions of said stud on opposite sides of said pole piece in such a manner that said stud is rigidly yet adjustably attached to said pole piece member in DC. isolation with respect to said pole piece.

9. The device as defined in claim 8 including a pair of ductile washer members disposed on said stud on opposite sides of said pole piece, each of said ductile washer members being sandwiched between a pair of insulating washers disposed on said stud.

10. A high frequency electron discharge device including a beam forming and projecting means coupled at the upstream end of said device to a tube main body portion and a metal beam collector member means coupled to said tube main body portion at the downstream end of said device, said device having an annular dielectric insulating member vacuum sealed between said tube main body and said metal beam collector member means, said tube main body forming a vacuum envelope in conjunction with said metal collector member means and said beam forming and projecting means, said device having mechanical support means physically yet insulatedly interconnecting said tube main body and said metal beam collector member means independently of and exterior to said vacuum envelope formed by said tube main body, beam-forming and projecting means and metal beam collector means, said annular dielectric insulating member being a ceramic rin-g, said ceramic ring being vacuum sealed to a pair of annular flexible expansion support ring-like members, said ceramic ring and said pair of expansion members forming part of the vacuum envelope of said device.

11. The device as defined in claim 10 including a plurality of said mechanical support members insulatedly yet adjustably interconnecting said tube main body and said collector means.

References Cited UNITED STATES PATENTS 2,684,452 7/1954 Sorg 31-292 X HERMAN KARL SAALBACH, Primary Examiner. ELI LIEBERMAN, Examiner.

P. L. GENSLER, Assistant Examiner. 

1. A HIGH FREQUENCY ELECTRON DISCHARGE DEVICE INCLUDING A BEAM FORMING AND PROJECTING MEANS COUPLED AT THE UPSTREAM END OF SAID DEVICE TO A TUBE MAIN BODY PORTION AND A METAL BEAM COLLECTOR MEMBER MEANS COUPLED TO SAID TUBE MAIN BODY PORTION AT THE DOWNSTREAM END OF SAID DEVICE, SAID DEVICE HAVING AN ANNULAR DIELECTRIC INSULATING MEMBER VACUUM SEALED BETWEEN SAID TUBE MAIN BODY AND SAID METAL BEAM COLLECTOR MEMBER MEANS, SAID TUBE MAIN BODY FORMING A VACUUM ENVELOPE IN CONJUNCTION WITH SAID METAL COLLECTOR MEMBER MEANS AND SAID BEAM FORMING AND PROJECTING MEANS, SAID DEVICE HAVING MECHANICAL SUPPORT MEANS PHYSICALLY YET INSULATED INTERCONNECTING SAID TUBE MAIN BODY AND SAID METAL BEAM COLLECTOR MEMBER MEANS INDEPENDENTLY OF AND EXTERIOR TO SAID VACUUM ENVELOPE FORMED BY SAID TUBE MAIN BODY, BEAM-FORMING AND PROJECTING MEANS AND METAL BEAM COLLECTOR MEANS. 